Method for extracting nylon from waste materials

a technology of waste materials and nylon, which is applied in the direction of dyeing process, textiles and papermaking, polymer recovery, etc., can solve the problems of reducing the temperature at which nylon is in waste materials, and achieve the effect of increasing the head pressure, increasing the pressure of solvent mixture, and lowering the dissolution temperature of nylon

Inactive Publication Date: 2010-02-09
INTERFACE INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0017]The increase in pressure of the nylon and alkanol-containing solvent mixture can be accomplished by introducing inert gas into the dissolution vessel, which is desirably a pressure vessel. Alternatively, the increase in pressure of the solvent mixture can be accomplished by increasing the head pressure of the solvent mixture pumped into the reactor. For instance, the vessel through which solvent is introduced to the reactor could have a cross-sectional area that exceeds that of the vessel through which solvent is withdrawn from the reactor, creating a pressure head in the reactor sufficient to lower the nylon dissolution temperature, and thus the reactor temperature, as described herein.

Problems solved by technology

The use of an elevated pressure has been found to unexpectedly decrease the temperature at which the nylon in the waste material will effectively dissolve in the solvent mixture.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0026]A series of tests were conducted wherein nylon yarn or nylon chips were tested to determine a baseline relative viscosity. Nylon chips were also dissolved in a methanol / water mixture, the nylon recovered, and its relative viscosity measured. A number of nylon-containing carpet tiles (designated as Sample Nos. 1-6) were chopped up and placed into a pressure vessel to which 400 ml of an alkanol solvent and 100 ml water were added as indicated below, and the mixture heated and pressurized as indicated below. The solution was removed from the pressure vessel into another vessel, where it was cooled until nylon precipitated. This nylon was then tested for relative viscosity using the same method that was used for the nylon yarn or chips. The results are indicated below.

[0027]

SolventDigestion(80%Final Pressure,RelativeSamplesTemp., ° C.Concentration)psigViscosityNylon 6,6Not digestedNANA44YarnStandard PANot digestedNANA4566 Standard PA165Methanol2053466 116599%14040Isopropanol2165De...

example 2

[0028]A similar procedure to that used in Example 1 was followed, using two samples from the same carpet tile or broadloom carpet, and varying the pressure thereof. The results are reported below. Where “Methanol” and “Pure Ethanol” are indicated, 400 ml. of these solvents were mixed with 100 ml of water. Where “100% Methanol” is indicated, water was not included in the mixture. Samples 1 and 3 were taken from carpet tile, Sample 2 was taken from broadloom carpet, and Sample 4 was taken from hot-melt precoated carpet.

[0029]

DigestionFinalTemp.,Pressure,ViscosityRelativeSamples° C.SolventpsigNumberViscosityNylon 6,6NotNANA13544YarnDigestedStandardNotNANA13745PA 66DigestedStandard165Methanol20511234PA 661A155100%21014147Methanol1B155Pure Ethanol150141472A155100%21016260Methanol2B155Pure Ethanol15016662

example 3

[0030]An 80% mixture of ethanol and water was preheated to the temperatures indicated below, and added all at once to a vessel containing nylon fiber in sufficient amount to provide a 3.5 wt % mixture of solvent and nylon. The mixture was pressurized to the pressure indicated below, and held at pressure for the time indicated below. The liquid was removed from the vessel and cooled in a jacketed vessel to a temperature of 120° C. The resulting cooled liquid was filtered to removed precipitated nylon. The undissolved nylon remaining in the first vessel was measured, and a yield of dissolved nylon to total nylon added to the mixture was computed.

[0031]

TemperatureRun(° C.)Pressure (psig)Time (min.)Yield (%)1143300376421434002382314745023100 415050015100 51601504588

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Abstract

The invention relates to a method for recovering nylon from a nylon-containing material by contacting the nylon-containing material with an alkanol-containing solvent at elevated temperature and at a pressure higher than the equilibrium pressure of the alkanol-containing solvent at the elevated temperature, thereby dissolving the nylon in the alkanol-containing solvent, removing the alkanol-containing solvent containing dissolved nylon from any undissolved solids, and decreasing the temperature of the alkanol-containing solvent containing dissolved nylon to precipitate the dissolved nylon.

Description

[0001]This application claims benefit of provisional U.S. application Ser. No. 60 / 245,006, filed Nov. 1, 2000, the entire contents of which are incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to improved processes for extracting nylon from waste materials, including mixed waste materials such as floor coverings, such that degradation of the nylon polymer into lower molecular weight polymers, oligomers, and monomers is decreased. The process involves contacting the waste materials with polar solvents, or mixtures thereof at high pressures.[0004]2. Description of Related Art[0005]Nylon is widely used as a fiber, both in the production of textile cloths, and in the production of floor covering materials, such as broadloom carpet and carpet tile. When used in floor covering materials, the nylon is usually predominantly present as part of one or more layers of a multilayered product. Large quantities of floor coverin...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): C08J11/08B01D9/02
CPCC08J11/08Y02W30/701C08J2377/00Y02W30/62
Inventor BERARD, RAYMOND A.
Owner INTERFACE INC
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